The proposed technology aims at creating a simple, low-cost and rugged cell analyzer capable of enumerating different populations of white blood cells, all lymphocytes, CD4 T-cells and the percentage of CD4 T-cells among all lymphocytes, directly from a small whole blood sample collected by finger prick. This technology is intended to be field deployable and to address the need for monitoring of HIV infected individuals, including children and infants, living in remote areas of resource-poor countries. A combination of techniques, including the immuno-magnetic capture and optical detection of biological cells will enable the isolation, identification and enumeration of T-Cells including the sub-population of CD4T-cells, B-Cells, and Natural Killer Cells directly from a complex sample matrix. PUBLIC HEALTH RELEVANCE: The proposed technology is designed to provide a low-cost, low-consumption and rugged field deployable diagnostic tool capable of isolating, identifying and enumerating biological cells directly from a small volume of specimen including whole blood. This new cytometer is ideally suited to respond to the current challenges of point-of-care diagnostics and to fill the gap that exists in regions with low health-care infrastructure such as in Sub-Saharan Africa where pandemic diseases like HIV/AIDS, TB and Malaria are the cause of million of deaths every year.